Tube bending machine with pivotally mounted adjustable pressure dies



May 19, 1959 F. BowER ETAL 2,887,141 TUBE BENDING MACHINE WITH PIVOTALLY MOUNTED ADJUSTABLE PRESSURE DIES Filed March 16, 1955 5 Sheets-Sheet `1 H H BD E@ ME BM L11/ NT Da Y BE May 19, 1959 B. F. BowER ET AL 2,887,141

TUBE BENDING MACHINE' WITH PIVOTALLY MOUNTED ADJUSTABLE PRESSURE DIES Filed March 1e, 1955 3 Sheets-Sheet 2 f2.3

iii

JZE'ZT 227.215-

BYRON F Bowie Y ROBERT J, MEBEDITH May 19, 1959 B. F. Bowl-:R ET AL 2,887,141

TUBE BENDING MACHINE WITH PIvoTALLY MOUNTED ADJUSTABLE PRESSURE DIES I Filed March 16, 1955 5 Sheets-Sheet 3 ...ZTTZEJTZDEE BY/ao/v F. Bowel? BoBEPT J. MEPED/TH W l En-E l United TUBE BENDING MACHINE WITH PIVOTALLY MUNTED ADJUSTABLE PRESSURE DIES t Application March 16, 1955, Serial No. 494,750

3 Claims. (Cl. 153-33) This invention relates to improvements in tube bending apparatus and more particularly to a tube bending machine having relatively movable pressure and bending dies of the type described in the specification of the co-pending application Serial No. 469,338, iiled November 17, 1954, now Patent No. 2,837,928 of which this application is a continuation-in-part.

Usually, tube bending machines are provided with a stationary bending die against which a length of tubing is clamped. A pressure die is so mounted as to move along the clamped tubingand thereby bend the tubing to the contour of the bending die.

In the present invention, there is provided a pair of pressure dies mounted for rotation toward and away from each other. A predetermined pressure is exerted on the dies to normally maintain them in aligned position to receive a length of tubing to be bent. The dies are mounted in adjacent relation to swing away from each other when a reciprocating bending dieis moved against the tubing in alignment with an axis between the pressure dies. When the pressure exerted by the movable bending die exceeds the opposed predetermined pressure exerted on the pressure dies, the pressure dies swing away from each other thereby eecting a bending of the tubing between the dies.

This arrangement of a single set-up of dies permits the forming of bends up to angles of 180, etects a greater working clearance by locating the dies in spaced relation to obstructions on the bending machine frame, and allows for multiple bends in various planes by the manual lengthwise shifting and rotation of a length of tubing in the pressure dies between strokes of the bending die.

It is, therefore, an important object of this invention to provide a tube bending machine having dies so constructed and arranged as to eifect a wide range in the angularity of bends which may be accomplished.

Another object of the invention is the provision of a tube bending machine having a bending die arrangement which lends itself to a location to provide maximum working clearance for tubing to be worked on.

A further object of the invention is the provision of a tube bending machine having bending dies which, with but one relative adjustment, permit the accomplishment of multiple bends in various planes in a single length `of tubing.

A still further object of the invention is the provision of a tube bending machine having a bending die arrangement which is simple in design, rugged in construction, simple in operation and highly eflcient in use.

Other and further objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description` of the annexed sheets of drawings, which disclose preferred embodiments of the invention.

On the drawings:

Figure l is a front view in elevation of a tube bending machine embodying our invention. of relatively movable Patent 2,887,141 Patented May 19, 9

pressure and bending dies and the pressure operating mechanisms therefor;

Figure 2 is a side elevational view of the tube bending machine construction shown in Figure l;

Figure 3 is an enlarged fragmental view in elevation of a pressure die cylinder, shown in normal position in full lines and shown in a position to which it is swung7 during operation of its connected pressure die, in dotted lines;

Figure 4 is a diagrammatic view of the rotatable pressure dies when in normal position at the start of a bending cycle and showing a length of tubing to be bent;

Figure 5 is a view, similar to Figure 4, illustrating the rotation and cooperation of parts when the dies have been moved to a tube bending position; and,

Figure 6 is a diagrammatic view of the tube bending dies and the operating and control mechanisms therefor, shown in normal position at the start of a bending cycle.

Referring now in detail to the drawings, and as ex plained in the specification of the said co-pending application for patent, our invention is shown as being embodied in a tube bending machine 20. It is, of course, to be understood that the bending die arrangement of this invention may be used in yassociation with any reciprocating device, whether vertical or horizontal,

The tube bending machine 20 includes a base 21 and a main frame 22. A secondary frame 23 is mounted on the face of the main frame and supports a bending ram construction 24. Spaced guide members 25 and 26, on the secondary frame 23, form a slide for receiving a reciprocating ram 27. The ram has a body 28 including a hollow parallelepipedon extension 28a with wing slides 29 and 30 seated between the frame 23 and the guide members 25 and 26. This construction permits the ram to slide lengthwise of the guide.

A piston 31, within the extension 28a, has a piston rod 32 extending through body 28 and depending from a support 33 attached by bolts or other suitable means to the frame 23. It will be noted in Figure l that a reduced end 34 of the piston rod extends through the support, and a nut 3S or other suitable attaching means holds the piston and rod against vertical movement. This is for a purpose to be described more fully later.

A bending die 36 of generally semi-circular `shape is carried at the end of the body extension 28a. It is preferred that the die be removably attached. l

ln the structure so lfar described, the body 2S moves relative to the stationary piston when fluid under pressure is introduced at an end of the cylinder.

A support table 37, mounted on the main frame 22 of the machine and located beneath the secondary frame 23, carries a pressure die mechanism 33. A supporting bed member 39 is secured to the table by means of bolts 40, 40, or the like. A pair of housings, a left hand housing 41 and a right hand housing 42, are mounted for sliding adjustment along the bed member 39 laterally across the tube bending machine. A slot, 43 extending lengthwise of the bed member, receives therein .an adjusting nut 44 on the housing 41 and an adjusting nut 45 on the housing 42. At the end of the bed member 39, supporting the housing 41, is a'bearing plate 46 attached to the bed member by means of bolts 47, 47, or the like. The operating end of an adjusting screw 48 is retained in the bearing plate and the screw extends through the housing adjusting nut 44 whereby to adjust the housing 41 toward and away from the housing 42. As best shown in Figure 2, inverted T-shaped slots 49 and 5t) are provided lengthwise of the bed member to receive therein bolts 5l and 52 which extend through a foot portion 53 of the housing 41 to secure the housing in an adjusted position. Similarly, a bearing plate S4 is attached to the opposite `end of the bed member by means of bolts 55, 55, or the y like. The operating end of an adjusting screw 56 is retained in the bearing plate and the screw extends through the housing adjusting nut 45i`-whereby to adjust the housing 42ftoward-and away from the housingr41.. Although not shown, bolts are provided to engagein the T-shaped slots 49v and 50 and extend vthrough a foot of .the housing 42 to secure the housing in an adjustedposition on the bed member.

Thel housing 41 has a cylindrical bore Vto rotatably receivera journal 57. At its forward end, vthe journal carries a die support 58. A pressuredie 59 seats on the support and is adjustably secured thereto. Bolts 60, 60 extend through slots 61, 61 in the die support toV clamp the die to the support. normal-to the die in order to provide-lateral adjustment of the die on its support. L'engthwise adjustment of the die is provided throughthe adjusting screw 48. Wedges 62 and 63, or similar means, provided either at one or both sides of the die, effect a desired lateral adjustment. A bearing plate 64, bolted to the die support 58k by means of bolts 65, 65 secures the adjusted die in position on the support. Similarly, a pressure die 66 is adjustably mounted on a die support 67, carried by a journal 68 extending into the housing 42, by means of wedges or other similar means (not shown) and secured or locked thereto by a bearing plate 69 with locking bolts 70 and 71.

As best shown in Figure l, the pressure dies 59 and 66 are adjusted 'along the die support S8so as to be located on opposite sides of and preferably equally spaced from the vertical axis of the bending die 36. Also, as shown in Figure 2, the pressure dies are adjusted laterally to align the tubing receiving grooves 72 and 73y with a similar'groove 74 in the bending die.

In Figures 4 and 5 are shown the cooperation of the bending and pressure dies by which a length of tubing 75 has a bend 76 formed therein. As the ram cylinder 28 moves the bending die 30 downwardly (as shown by arrows) against the tubing and in` alignment with the space between the pressure dies, the tubing bends around the bending die. The depth of the bend is determined by the distance the bending die moves in its association with the tubing and pressure dies. However, it is desirable that the bending die movement be so limited that the lines of contact between the tubingy and the bending die do not extend above the horizontal plane H through` the horizontal axis A of the bending die.

To insure the proper bending of the tubing75 by the downward movement of the bending die 36, it is necessary to provide each ofthe pressure dies 59 and66 with a backing pressure. The pressure provided should be such as to give when exceeded by the pressure exerted through the bending die 36. This backing pressure is exerted through means to maintain fluid pressure provided in cylinders 77 and 78.

A pair of wing supports 79 and 80 are attached to the secondary frame 23 atfthe upper end and on. opposite sides thereof. The wing support 79 extcndslaterally to locate the lower end of the attached cylinder 77 spaced from the housing 41. As shown in Figures l, 2 and 3, the upper end of the cylinder is provided with a pivot hanger 81 having therein an opening 82. A pivot pin 83 extends through the spaced sidewalls84 and 85 of the wing support member '79 and through the opening 82 of the pivot hanger 81 which is located between the wing sidewalls. This arrangement permits the cylinder 77 to swing on the pivot pin 83 in directions toward and away from the housing 41 and the verticallyl movable-reciprocating ram 27. A piston 86, within the cylinder '77, has extending therefrom a piston rod 87 with a. clevis 88 attached to its free end. An actuating arm 89 has one end 90 embraced on and securedto for co-rotation with the journal S7 at the rear'of the housing .41. The opposite end 91 of the actuating arm is arranged between'the legs of the clevis` 88 and pivotally secured thereto by a` pin 92.

As'shown .in Figures 4 and-5,` the-bending of tubing 75` Theslots are enlarged ina directionv effects a rotation of the journal 57 in a clock-wise direction, as shown by the arrow. As the free end 91 of the actuating arm 89 swings upwardly the connected clevis 88, the cylinder 77, piston rod 87 and the piston 86 swing outwardly and upwardly. The piston 86 thereby moves against any fluid in the cylinder 77.

A similar arrangement is provided with the cylinder 78. A pivot hanger 93 on the upper end of the cylinder is connected to and between spaced sidewalls (not shown) of the wingsupport by means of a pivot pin 94. A piston 95, within the cylinder, has extending therefrom a piston rod 96 with a clevis 97 at its free end. An actuat ing arm 98 has one end 99 embracing that portion of the journal 68 to the rear of the housing 42 and is secured to the journal for co-rotation therewith. The opposite end 100 of the actuating arm is pivotally connected to and between the sides of the clevis 97 by means of a pin,

101. As the bend 76 is formed, the pressure die 66, together with its connected journal 68,` is rotated within the housing 42 thereby eifecting a counter-clockwise rotation ofthe actuating arm 98. As the arrn rotates, the cylinder 78, rod 96, and piston 95 swing outwardly with the piston being moved into the cylinder against fluid l therein.

Figure 6 diagrammatically illustrates the general operating and control mechanisms of the tube bending ma* chine. A motor 102 drives a pump 103 that draws fluid, preferably a liquid such as oil, from a reservoir 104 through a suction line 10S. The iluid is then pumped through a conduit line 106 to a 4-way directional control .valve 107. This system is'intended to operate at a predetermined.pressure-which is maintained by bleeding sufficient lluid through a by-pass line 108 and a pressure relief valve 109 into the reservoir 104.

The directional control valve 107 is of well known construction and is shown as being manually operated by a handle 110 to direct the flow of iluid either to the upper end of the ram cylinder 28 through a conduit 111 or to the lower end of the cylinder through a conduit 112. By this manual control, the movable ram cylinder 28 is operated relative to the stationary piston 31. This movement controls the operation of the bending die 36 both relative to and in. cooperation with the pressure dies 59 and 66.

A conduit line 113 is in fluid flow connection with the line 106, between the by-pass valve 109 and the manually operated directional control valve 107, and extends into connection with an adjustable pressure control valve 114. A conduit 115 connects the pressure control valve 114 to an adjustable maximum pressure valve 116. Both pressure valves are of the one-way type, that is, pressure is exerted through each valve in but one direction. Conduit lines 117 and 118 are in fluid flow communication with the conduit 115, between the pressure valves 114 and 116, and extend, respectively, into connection with the upper ends of the cylinders 77 and `78. A return conduit 119 connects the maximum pressure valve 116 and the reservoir 104.

When the operating handle 110 of the directional control valve 107 is manually actuated to open the conduit 112 to fluid ow from the pressure line 106, the ram cylinder 28 actuates the bending die 36 into engagement with a length of tubing seated on the pressure dies 59 and 66. As abend is formed in the tubing, the pressure dies rotate with their respective journals thereby rotating the actuating arms-89 and 98.

Assuming, for purposes of example only, that a constant pressureis exertedthrough the conduit 106 to provide arbending pressure of 150.p.s.i. at the bending die 36, and, that aconstant back pressure of 50 p.s.i. is desired at the pressure dies 59`and 66I to resist rotation during the bending operation. The pressure control valve 114 is so adjusted as to provide a-constant pressure through-.the conduits 117 and 118 to the cylinders Y77 and 78 above tlieirirespectivepistonswhich, in turn, transmit the pressure through the piston rods, clevises, actuating arms, and journals to the pressure dies 59 and 66. Accordingly, the tubing is bent under opposed and unequal pressures.

As the bending pressure exerted by the bending die is greater than the resisting pressures of the pressure dies, a rotation of the pressure dies is transmitted to the operatively connected pistons 86 and 95. Movement of the pistons toward the ends of their respective cylinders effects an increase in the pressure in conduits 117 and 118. By adjusting the effective operating pressure of the maximum pressure valve 116 slightly higher than that of the pressure control valve 114, there is eiected a pressure bleeding into the return conduit 119.

There is thus insured, during the bending operation, the application of constant pressures on the pressure dies 59 and 66.

After a bend 76 is accomplished, the valve 107 is manually actuated to connect conduit lines 106 and 111 whereby to operate the ram cylinder and the bending die 36 away from the pressure dies 59 and 66. Release of pressure exerted by the bending die against the pressure dies effects a reverse movement of the pistons 86 and 95 as the maximum pressure valve 116 closes and pressure is again exerted through the pressure control valve 114.

It will be noted that a return iiow line 120 connects the valve 107 and the tank 104. When the valve is positioned to direct ow through lines 106 and 111, the lines 112 and 120 are opened to flow to the tank. Similarly, when the valve is positioned to direct flow between lines 106 and 112, the lines 111 and 120 are opened to flow to the tank.

As many bends, in the same or different planes, in a tubing may be accomplished as desired by manually moving an unbent portion of the just bent tubing into bending position and rotating the tubing to a new angle of bend.

Although the tube bending machine 20 is shown in preferred vertical position, it may, if desired, be constructed to reciprocate horizontally.

While I have shown certain preferred embodiments of my invention and described them more or less precisely as to details, it is to be understood that the invention is not to be limited thereby, as changes may be made in the arrangement and proportion of parts, and equivalents may be substituted, without departing from the spirit and scope of the invention except as required by the terms of the claims.

We claim as our invention:

1. In a tube bending machine, the combination of an upstanding frame, a support table adjacent to the lower end of said frame, a hydraulic bending die mechanism on said frame reciprocable toward and away from the support table, means regulating reciprocation of said mechanism, a pair of housings mounted on said support table, said housings being arranged in a common plane spaced from the path of said mechanism, means to adjust said housings toward and away from each other in said plane, a journal received in each housing and mounted for rotation about axes perpendicular to the said plane, said journals carrying die supports and positioned for swinging movement in the path of the bending die mechanism, pressure dies mounted one on each die support for adjustment relative to said supports in the direction of the journal axes, an actuating arm on each journal extending laterally from the journal axes, a piston rod operably connected one to each arm, and a hydraulic cylinder for each piston rod, said cylinders being pivotally mounted on the frame and above said table one on each side of the bending die mechanism for self adjustment upon adjustment of the housings.

2. In a tube bending machine, the combination of, an upstanding frame, a support table adjacent to the lower end of said frame, a hydraulic bending die mechanism on said frame reciprocable toward and away from the support table, means regulating reciprocation of said mechanism, a pair of housings mounted on said support table, said housings being arranged in `a common plane spaced from the path of said mechanism, means to adjust said housing and mounted for rotation about an axis peipendicular to the said plane, said journals carrying die supports and positioned for swinginst movement in the path of the bending die mechanism, pressure dies mounted one on each die support for adjustment relative to said supports in the direc tion of the journal axes, an actuating arm on each journal extending laterally from the journal axes, hydraulic means each including a piston and a cylinder operably connected one to each arm and each extending upwardly from the table on opposite sides of the frame and said bending die mechanism axis, and means pivotally mounting the cylinders at their upper ends to the frame above the table.

3. In a tube bending machine, the combination of, an upstanding frame, a support table adjacent to the lower end of said frame, a hydraulic bending die mechanism on said frame above and reciprocable toward and away from the support table, means regulating reciprocation of said mechanism, a pair of housings mounted on said support table and spaced apart in a common. plane spaced from the path of said mechanism, means to adjust said housings toward and away from each other in said plane, a journal received in each housing and mounted for rotation about an axis perpendicular to said plane, said journals carrying die supports positioned for swinging movement in the path of the bending die mechanism, pressure dies mounted one on each die support for adjustment relative to said supports in the direction of the journal axes, a radially extending actuating arm on each journal, a piston rod operably connected one to each arm, a hydraulic cylinder for each piston rod, means pivotally connecting said cylinders to the frame and above said table for self adjustment upon adjustment of the housings, and means to maintain Huid pressure in the cylinders to resist pressure on the pressure dies under the influence of the hydraulic bending die mechanism.

References Cited in the le of this patent UNITED STATES PATENTS 70,595 Mitchell Nov. 5, 1867 395,723 Vanstone lan. 8, 1889 1,258,892 Griffin Mar. 12, 1918 1,570,710 Schenck Jan. 26, 1926 1,938,768 Schulte lDec. 12, 1933 1,948,474 Meyer Feb. 20, 1934 2,018,040 Sweeney Oct. 22, 1935 2,327,440 Maize Aug. 24, 1943 2,437,092 Greene Mar. 2, 1948 2,440,599 Colwell Apr. 27, 1948 wan- UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No 2,887, l/.ll May 19, 1959 Byron F. Bower et alo It 'is hereby certified that error appears in the above numbered patent reqiiring correction and that Jche said Letters Patent should read as corrected below.

Column line 16, after "plane, insert journals mounted one in each housing for rotation on axes perpendicular to the axis of the bending die mechanism, M.

Signed and sealed this 29th day of December 1964.,

(SEAL) Attest:

ERNEST w1 swim-:R

EDWARD J. BRENNER A imsting Officer:

Commissioner of Patents 

